Direct Observation of Structural Defects in Laser-Deposited Superconducting Y-Ba-Cu-O Thin Films

• Published in: Science (American Association for the Advancement of Science) Vol. 247; no. 4938; pp. 57 - 59
• Main Authors: Ramesh, R., Hwang, D. M., Venkatesan, T., Ravi, T. S., Nazar, L., Inam, A., Wu, X. D., Dutta, B., Thomas, G., Marshall, A. F., Geballe, T. H.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for the Advancement of Science 05-01-1990; American Association for the Advancement of Science; The American Association for the Advancement of Science
• Subjects: 360602 - Other Materials- Structure & Phase Studies; ALKALINE EARTH METAL COMPOUNDS; Atomic structure; BARIUM COMPOUNDS; Condensed matter: structure, mechanical and thermal properties; COPPER COMPOUNDS; Critical current; CRYSTAL DEFECTS; Crystal lattices; CRYSTAL STRUCTURE; DATA; Dielectric films; ELECTROMAGNETIC RADIATION; Exact sciences and technology; EXPERIMENTAL DATA; High temperature superconductivity; Image resolution; INFORMATION; LASER RADIATION; Magnetic flux; Material films; MATERIALS SCIENCE; Mental imagery; NUMERICAL DATA; OXYGEN COMPOUNDS; Perovskites; Physics; Product defects and recalls; RADIATIONS; Solid surfaces and solid-solid interfaces; Superconductivity; SUPERCONDUCTORS; Surface and interface dynamics and vibrations; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; THIN FILMS; TRANSITION ELEMENT COMPOUNDS; YTTRIUM COMPOUNDS; Stoichiometry; High resolution; Transition metal Compounds; Stacking fault; Edge dislocation; Crystal defect; Experimental study; Inorganic compound; Thin film; Growth from vapor; Transmission electron microscopy; Laser beam; Superstructure; Barium Copper Yttrium Oxides Mixed; High temperature superconductor; Lattice image
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.247.4938.57

The defect structure of in situ pulsed, laser-deposited, thin films of the high-transition temperature superconductor Y-Ba-Cu-O has been observed directly by atomic resolution electron microscopy. In a thin film with the nominal composition YBa$_2$Cu$_3$O$_7$ (123), stacking defects corresponding to the cationic stoichiometry of the 248, 247, and 224 compounds have been observed. Other defects observed include edge dislocations and antiphase boundaries. These defects, which are related to the nonequilibrium processing conditions, are likely to be responsible for the higher critical currents observed in these films as compared to single crystals.